Mechanism for locating two printing plates on stereotype plate finishing machine



Jan. 29, 1963 c. s. CRAFTS MECHANISM FOR LOCATING TWO PRINTING PLATES 0N STEREOTYPE PLATE FINISHING MACHINE 2 Sheets-Sheet 1 Filed Oct. 11, 1960 INVENTQR.

CURTIS 5. CRAFTS 2! ATTYS.

Jan. 29, 1963 c. s. CRAFTS 3,075,276

MECHANISM FOR LOCATING TWO PRINTING PLATES ON STEREOTYPE PLATE FINISHING MACHINE Filed Oct. 11, 1960 2 Sheets-Sheet 2 I37 I g 5 I39 H34 I 44: "5k: -jr I a \\J svw I35 lwvzw'ro Q CURTIS S. CRAFTS 54am ATTYS.

United States Patent Ofiice 3,@75,Z76 Patented Jan. 29., 1963 5 3 6 MECHANISM FOR LGCAT-ING TWO PRINTING PLATES 0N S'IEREOTYPE PLATE FINISHING MACHENE Curtis S. Crafts, ()ak Park, 111., assignor to Miehle-Goss- Dexter, Incorporated, Wilmington, Deh, a corporation of Delaware v Filed Oct. 11, 1960, SenNo. 61,948 1 Claim. (Cl. 2-21) This invention relates to stereotype printing plates and more particularly to means for locating tabloid page size stereotype printing plates during the step of milling tension lock-up pockets in the under side of such printing plates on'a stereotype plate finishing machine.

Modern newspapers ,are, generally speaking, given a format in either of two 'sizes, namely: full or regular page size newspapers and half-size newspapers known as tabloids. Heretofore in the printing of -tabloid newspapers it has been the practice to use full size semi-cylindrical plates, each full size plate-bearing the impression to print two tabloid pages.

In color printing processes, the individual colors are printed in separate impressions and by plates prepared especially for a particular color. Pour colors are commonly used and they are individually printed successively on the moving web in newspaper presses, the last color usually being black. The color plate must be accurately positioned on the printing cylinder so that 'each color will register accurately with previously printed colors in order to produce a satisfactory reproduction. It is thus necessary for the printing cylinder to include means [for adjusting the position of the plate relative to the cylinder so that it will register accurately with th'epreviously printed colors.

In the printing of tabloid size newspapers, the stereotype printing plate bearing the impression for the front 'hot news page of the newspaper, usually includes the impression to print the back page of thepaper, which may include an ad in a particular color. The news content ofthe front page often must bechanged for dilfe'rent editions, but in most instances from edition to edition the back page, or at least the ad portion, remains the same. Therefore, when the news changes the entire full size plate, including that portion ofthe plate whichjbears the impression to print the back page, will have to be replaced. This is wasteful in terms of labor cost.

Furthermore, when ,a new full size plate containing later news copy on one half and the same ad copyon the other half is prepared, it is likely that the .ad copy will not be in exactly the same location on the plate with respect to the plate lock-up mechanism, as itwas in the previous plate. Therefore, the new plate will have to be readjusted on the printing cylinder so that the color will be in register with previously printed colors before the later edition can be run ofi. This adjusting is tedious and time consuming, thus contributing to higher costs. Changes in position of the news copy on the new plate and printed page will not be noticeable and can be disregarded, but the plate must be registered Within a small fraction of an inch so that the copy for the ad will register with other parts (colors) of the ad.

I have discovered a method for preparing tabloid page size stereotype printing plates \for printing color or news in tabloid newspapers on printing presses equipped with suitable plate holding cylinders. With the stereotype plate prepared in accordance with this method, tabloid newspapers may be printed more economically, for these wasteful practices are eliminated. Thus, while the major part of the tabloid newspaper may be printed in conventional fashion, with full size printing plates bearing the impression of two tabloid pages, those pages of the news paper requiring change from edition to edition may be printed by means of individual tabloid page size plates, which may be changed as required without disturbing (the plates which have been precisely registered to print color. Plate holding cylinders suitable for the employment of tabloid page size plates are disclosed in'Patent No. 2,915,010, issued December '1, 1959, to Curtis S. Crafts. The preceding description indicates that two sizes of stereotype plates may be used and it should be understood that the term tabloid size plate, as used hereafter, means a stereotype printing plate equal in size to one page of a tabloid newspaper, while the term full size plate means a plate equal in size to one standard newspaper page.

This method for making tabloid stereotype printing plates involves the steps of casting a full size semi-cylindrical stereotype plate with the type impression on the periphery of it to print two tabloid pages and finishing the under side of the plate; cutting rows of tension lock-up pockets adjacent the straight edges of the full size plate; cutting the plate betweenthe tabloid pages to form two individual tabloid size printing plates; and, finally, milling tension pockets adjacent the newly cut edge of these individual plates. During the final milling operation, the plate is accurately located by means of the previously cut row of lock-up pockets, 'to insure that the new row of pockets is correctly positioned on the under side of the tabloid plate.

The principal object of this invention is to provide apparatus for locating stereotype plates during the final operation of milling tension lock-up pockets in the under side of such individual tabloid size printing plates. A more detailed and related object thereto is to provideplate locating mechanism for precisely and accurately position- Jin'g a pair of platesin the apparatus during the final milling operation. As described hereinbefore, I have discovered that tabloid size printing plates may be made by separating or sawing a full size plate in two, this full size plate having previously been processed to form rows of tension pockets in the finis'hed'under side of the plate, thus leaving the individual plates with a single row of tension pockets adjacent only one edge. It is an object hereof to utilize this row of pockets in backs of the tabloid size plates, for locating the pair of plates during the operation of cutting the second row of pockets in them, so that the parallel rows of pockets in the finished plates are spaced accurately. Other objects will appear from the following description taken in connect-ion with the accompanying drawings, in which:

FIGURES 1 and '2' areperspective views of semi-cylindrical or full size stereotype ,printing plates .for printing newspapers of regular page size and tabloid page size, respectively;

FIG. 3 is a perspective view of a .pair of tabloid size stereotype printing plates, one of which is shown in dashed lines, made 'from the full size plate shown in FIG. 2;

FIG. -4 is a perspective view of a machine for milling tension lock-up pockets in stereotype printing plates;

FIG. 5 is a sectional view with some parts added, taken through the saddle of the machine of FIG. 4, illustrating the mechanism for locating tabloid plates on both sides of the saddle of the machine;

FIG. '6 is an enlarged fragmentary view in side elevation of the wedge mechanism for forcing the plates against the locating hooks;

FIG. 7 is .an enlarged fragmentary plan view of the plate locating mechanism; .and

FIG. 8 is an enlarged fragmentary transverse sectional view taken substantially in the transverse plane including lines "8-8 of FIG. -6

While the invention is shown and described in detail with reference to particular embodiments thereof, there is no intention that it thus be limited. On the contrary, it is intended to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention as defined in the appended claim.

Referring now to the drawings, FIGURE 1 illustrates a full size, semi-cylindrical, stereotype printing plate 10. This plate might be used, for example, in the printing of a full size newspaper page in one of the dailies printed in our large cities. Tabloid newspapers, having pages half the size of the full size newspaper, are ordinarily printed by means of plates similar in size to that shown in FIGURE 1, but like the plate 11 illustrated in FIG. 2 bearing on its periphery the impression for two tabloid size pages 12, 13. Both the plates shown in FIGURES 1 and 2 are provided with rows of tension lock-up pockets 14 on the finished, concave under side surfaces, for cooperation with tension lock-up mechanism on the printing cylinder. Reference is made to Chase et al. Patent No. 2,639,668 for a description of a printing cylinder equipped with tension lock-up mechanism for holding in place stereotype printing plates of the type illustrated in these two figures of the drawings.

The present invention in one respect is concerned with the improvement in printing tabloid newspapers whereby, in place of employing the full size stereotype printing plate 11 illustrated in FIG. 2 which prints two pages, individual tabloid size printing plates (12 and 13, FIG. 3) are employed for printing certain of the tabloid pages.

It is contemplated that the pages to be printed by means of individual tabloid page size plates are those pages of the newspaper requiring revision from edition to edition, as for changing the news content. Accordingly, using this method of printing tabloid newspapers, it will be possible to replace only the plate requiring revision and thereby eliminate the wasteful practice wherein semicylindrical plates bearing the impression to print two pages have had to be replaced where only one of these two pages requires revision. Substantial economies in labor costs may thus be effected.

Accordingly, turning now to FIGURE 3, the present invention contemplates making stereotype printing plates containing copy for a single page for printing newspapers of tabloid size. Furthermore, in order that these tabloid size plates 12 and 13 may be secured to printing cylinders equipped with tension lock-up mechanism, each tabloid size plate is provided on the under side with parallel rows of tension lock-up pockets adjacent each straight edge and properly spaced for engagement by plate holding fingers on the printing cylinder.

Manufacture of Tabloid Plates Heretofore, stereotype printing plates for both regular and tabloid newspapers have been made by casting semicylindrical plates which are finished by trimming the ends and machining the under side surface to accurate dimensions. If the plate is to be secured to the printing cylinder by a tension lock-up arrangement, rows of tension lockup pockets then are milled in the under side of the plate.

An exemplary machine Ztl for milling tension lock-up pockets in the under side of a full size, semi-cylindrical printing plate is shown in FIG. 4. This machine is of the type illustrated and described in copending application Serial No. 641,176 of Glenn N. Krueger, filed February 19, 1957, entitled Machine for Finishing Stereotype Printing Plates. Essentially, and insofar as important here, the machine includes a base 21, a housing 22 shrouding a motor (not shown) for powering the milling cutters 23 (FIG. and a saddle 24 on which an inverted stereotype plate 25, with the ends already trimmed and the under side 28 machined to the finished dimension, may be held by means of clamps 29, while the tension lock-up pockets 14 are milled by means of the milling heads 23. These milling heads are pivotally supported so as to be oscillateble into and out of engagement with the under side of the plate supported on the saddle, the saddle itself being formed with elongated openings 31 in the region of, or adjacent the milling heads, through which the heads project when milling tension lock-up pockets in the plate. The machine illustrated in FIGS. 4 and 5 mills rows of tension lock-up pockets adjacent the straight edges of the plate with precision and accuracy.

While the foregoing description applies to the milling of tension lock-up pockets in the under side of a full size printing plate bearing the impression to print the page of a regular size newspaper, it, of course, applies just as aptly to the milling of tension lock-up pockets in a full size plate which bears the impression to print two tabloid size pages. Thus, referring to FIG. 2, the printing plate there shown may be clamped in the apparatus of FIG. 4, and rows of tension lock-up pockets milled in the plate, to prepare the plate for use on a printing cylinder equipped with tension lock-up mechanism, and for printing a tabloid newspaper.

The first step in making tabloid size stereotype printing plates is the same as has been followed heretofore in preparing full size plates. In other words, a full size, semi-cylindrical plate is cast with the type impression for two tabloid size plates on the periphery of it. Next, the plate is trimmed, finished, and tension lock-up pockets cut in the under side of the plate adjacent both its straight edges.

The full size plate, shown in FIG. 2, is then cut in two between the two tabloid pages leaving two halves, each constituting a tabloid size plate for printing one tabloid page, as shown in FIG. 3. At this stage in the preparation of tabloid size plates, it should be noted that each plate has tension lock-up pockets along one straight edge.

The final step in preparing a tabloid size plate is the cutting of a second row of tension pockets in the concave under side, properly spaced from the existing pockets for engagement by the tension lock-up mechanism of a printing cylinder, shown, for example, in Patent No. 2,915,010 to Curtis S. Crafts, for locking tabloid plates in position on the surface of the cylinder. To insure that the rows of tension pockets are spaced at exactly the right distance to receive such lock-up mechanism, the present invention provides means for accurately locating the plate on the saddle while milling the row of tension pockets adjacent the newly sawed edge of the plate. As mentioned previously, each tabloid plate already has a row of pockets adjacent one straight edge, and the invention contemplates employing these pockets for locating the plate accurately during the final milling operation.

The Tabloid Plate Locating Mechanism Referring again to FIG. 4, the saddle 24 of the machine there depicted is provided with means for simultaneously locating on the saddle a pair of tabloid size plates, made by cutting a finished full size plate in half for the operation of milling the second rows of pockets in the plates. A pair of tabloid plates, each having one row of pockets, are positioned by the locating means so that the new row of pockets produced by the milling apparatus will be spaced from the existing row of pockets. at the exact distance to receive the lock-up mechanism on the printing cylinder. With the plates so located on the saddle 24 of the machine, the clamping means 29 is applied to clamp the plates securely on the saddle for the milling operation.

The plate locating mechanism 119, FIGS. 5, 6 and 7, is installed in the saddle near the center line of the crown and provides means for engaging existing tension lock-up pockets in two tabloid plates, one on each side of the curved saddle. The plates are positioned so that the new pockets 122 out by the milling cutters 23, as shown in FIG. 5, are accurately spaced from the existing pockets 1 Referring to FIG. 5, it will be seen that, as herein shown, this locating mechanism 119 embodies an assembly including locating hooks 12%, 121 arranged in pairs on each side of the longitudinal center line of the saddle 24. The hooks are mounted to engage two of the existing pockets 14 in tabloid plates on each side of the saddle, for positioning them accurately so that a second row of pockets can be milled along the sawed straight edge of the plate. In the present instance, as shown in FIG. 7, the hooks of each pair are spaced longitudinally on the saddle so as to engage the end pockets of the plates. The locating hooks 120, 121 are movably mounted so that they may be positioned below the surface of the saddle within a cavity 124 or may be manually rotated to a position where they extend above the surface of the saddle to engage the existing pockets 14 in tabloid plates, in which position the hooks are shown in FIG. 5. Referring to the same figure, the locating hooks are pivotably supported on rods 126, 127 which are carried by a machined segment 128 which itself is mounted on the top of the saddle 24 within a transverse cavity 129.

The outside surface of the segment 12% conforms to the surface of the saddle and provides a continuation thereof except for the recess or cavity 124 for receiving the locating hooks 12%, 121. The opposite end walls 139 of the cavity or recess within the segment 12$ are vertical and accurately machined to provide a stop against which the back 131 of each locating finger bears when in the outward position depicted in FIG. 5. To resiliently maintain the locating fingers in either position, a nose portion 132 is provided which bears against a flat spring 133.

In this form of the invention, a wedge 134 is employed for forcing the tabloid page size plates against the cating hooks, to prevent shifting on the saddle when clamping is applied. As shown in FIGS. 5 and 8, this wedge is mounted to move vertically within a slide provided in a bracket 135 mounted above the crown of the saddle, for example, by means of bolts, upon the arcuate, rigid backing supports for the plate clamps 29 provided for clamping the plate on the saddle of the machine. The wedge 134 may be forced against the plates by means of a wedge handle 136. This wedge handle may actuate the wedge by means of a pin 137 which is fastened to the wedge handle and extends through opposite slightly enlarged openings 138 which are provided on cars 139 above the body of the wedge. This connection provides a limited range of movement of the wedge handle 136 from a horizontal position, as shown in solid lines in FIG. 6, to an angularly extending raised position as shown in dash-dot lines in this same figure. Spring biased detents 140 and detent wells 141 (FIG. 8) are employed for holding the wedge in its raised position spaced away from the saddle so as not to interfere with operating the machine to mill tension lock-up pockets in full size stereotype plates.

With this form of the invention, both tabloid plates formed from one semi-cylindrical plate may be positioned on the machine without turning either plate end for end on the saddle. A plate finishing machine as shown in FIGURE 4 may include features for use in preparing full size semi-cylindrical plates for printing color, such as image registering mechanism, plate stops and skewing devices. Ordinarily, such a machine also provides a cutter 142 on each side of the machine which trims one end of the full size plate to provide a reference surface 143, 144 at both corners (FIGURE 1) for sidelay register purposes. With the locating mechanism here shown, the tabloid plates may be positioned on the saddle in the same endwise relation they originally held while part of the full size plate, but shifted to a position on the opposite side of the saddle. When the tabloid plates are so positioned, the same trimming cutters may be utilized for trimming the other corners of the tabloid plates so that two surfaces will be prepared for engagement with locating pins on the plate cylinder.

Referring to FIG. 5 it will be noted that the plate 10- cating means there disclosed includes members on each side of the center line along the crown of the saddle which may engage, when pivoted to extend above the surface of the saddle, the existing tension lock-up pockets along one straight edge of tabloid size plates when carried on the saddle. The arrangement there shown is provided for a pair of tabloid size plates 123 that originally formed, together, a single semi-cylindrical printing plate.

Following the procedures outlined hereinbefore, the locating hooks 120, 121 are positioned below the surface of the saddle, the wedge 134 is raised, and a semi-cylindrical plate with the impressions of two tabloid pages is placed on the saddle of the milling machine as shown in FIG. 4 and rows of tension pockets are cut along the straight edges of the plate, producing a plate as shown in FIG. 2. After this operation has been completed, the plate is removed and sawed along the center line between the tabloid pages thus providing two tabloid size plates.

The locating members on the crown of the saddle are then raised, the clamps moved out of the way, and the two tabloid plates placed on the saddle with the locating members in pockets in the plates. So positioned, the tabloid plates may be on the opposite side of the saddle from the original position when part of the full size plate. The clamping means is then slid lengthwise to a position over the plates and applied to clamp the tabloid plates rigidly for the milling operation in which rows of pockets ape cut adjacent the newly sawed edges of both tabloid p ates.

As pointed out previously herein, the finishing machine provides a cutter 142 on each side which trims one end of the semi-cylindrical plate at both corners for sidelay register purposes. It should be obvious that a tabloid plate produced with the procedure described herein will have a trimmed corner on one side only. The machine permits these same cutters to be used for trimming the other corners of the tabloid plates by providing the Plate positioning means on both sides of the saddle. With this provision each plate can be carried on the saddle without being turned end for end, and the corner adjacent the newly sawed edge then becomes positioned adjacent the trimming cutter 142 for trimming this corner for sidelay register purposes.

I claim as my invention:

In a machine for milling tension lock-up pockets in semi-cylindrical printing plates, the combination comprising, a saddle providing a cylindrical reference surface, means overlying said reference surface and engageable with a plate carried on said reference surface for clamp ing said plate on said saddle, means for positioning two tabloid plates on said saddle, said means for positioning including a row of plate locating members carried on the crown of the saddle on each side of the center line thereof, means for mounting said members for movement from a position below the reference surface to a position above the surface wherein said members are receivable in pockets adjacent one straight edge of the tabloid plates so as to define desired locations for the latter on both sides of the saddle, means including a wedge carried over the crown of the saddle between said tabloid plates for engaging straight edges of such plates, and means for forcing said wedge downwardly between the plates to urge said plates mutually away from each other and solidly against said members for accurately positioning the plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,312,073 Bechman Aug. 5, 1919 2,085,908 Huck July 6, 1937 2,945,284 Crafts July 19, 1960 

